This program is directed primarily at increased understanding of regulation of peripheral circulation. It approaches this regulation on a variety of levels, extending from effects of emotion to effects of peripheral receptors, such as baroreceptors and chemoreceptors, through consideration of regulation of particular vascular beds (e.g. coronary, skin, muscle, splanchnic, bone), distribution of blood flow, and detailed examination of regulation of microcirculation. Experimental preparations are also widely distributed, extending from anesthetized animal preparations through intact, unanesthetized experimental animals and humans. We seek to investigate details of regulation in arterioles, precapillary sphincters (i.e. at sites where ultimate control is investigated), and details and relative importance of local metabolic control versus autonomic control. We will investigate existence of 'patterns' in autonomic discharge to various organs and changes in these autonomic patterns under a variety of stresses. Where possible, we will produce a quantitative description of the phenomena under study, extending to understanding the quantitative significance of regional vasomotor activity in redistribution of blood flow and in regulation of total peripheral resistance and blood pressure. Thus, ultimate goals of the study are both broad and narrow. Certain broad questions are capable of being answered now, while questions involving state of knowledge with respect to particular organs will be more detailed and less general. BIBLIOGRAPHIC REFERENCES: Brengelmann G. L., M. McKeag, L. B. Rowell. Temperature control system for water-perfused suits. J. Appl. Physiol, 1977, in press. Brengelmann G. L. Control of sweating rate and skin blood flow during exercise. In Problems with Temperature Regulation During Exercise, edited by E. Nadel. New York, Academic Press, 1977, in press.